"Our Starlink team last exchanged an email with the Aeolus operations team on August 28, when the probability of collision was only in the 2.2e-5 range (or 1 in 50k), well below the 1e-4 (or 1 in 10k) industry standard threshold and 75 times lower than the final estimate. At that point, both SpaceX and ESA determined a maneuver was not necessary. Then, the U.S. Air Force's updates showed the probability increased to 1.69e-3 (or more than 1 in 10k) but a bug in our on-call paging system prevented the Starlink operator from seeing the follow on correspondence on this probability increase - SpaceX is still investigating the issue and will implement corrective actions. However, had the Starlink operator seen the correspondence, we would have coordinated with ESA to determine best approach with their continuing with their maneuver or our performing a maneuver."

ESA’s chain of twitter comments makes me think this was really more of an opportunity for them to publicize their upcoming automatic collision-avoidance system. Basically this is an exercise in self-promotion (and taking a pot shot at SpaceX along the way).

I'm sure there is an application for neural networks in optimizing orbital maneuvering, especially in the crowded LEO. There are a lot of uncertainties and no one can really calculate the 'perfect' maneuver without taking into account a million variables and even then there's plenty uncertainty. Right now collision avoidance is a manual operation (with computer models of course), maneuvers are worked on by very skilled engineers and mathematicians. In the future collision avoidance will likely become so common that an automated system, or a AI based tool at the very least will be necessary.

Yes, it is effectively advanced statistics. By "hard math" I mean the use of multivariable and computational statistics to find an efficient avoidance maneuver. Compared to ML which is considered "fuzzy" because it relies on a set of seemingly random relationships instead of a set input-output problem with uncertainty.

I’m trying to teach myself some math, and I’m in this space where it feels like you could solve anything with Fourier analysis and statistics. But I suppose it does make sense that a 4-dimensional vector like a single orbital maneuver is still a very large domain space to have to explore.

So I’m guessing they can rigorously define the value number of a given (multi-m(t,Δv) chain?) maneuver, and let a neural net make a close-enough-to-equivalent “shortcut” of a full summation of the problem space. That is, the results desired are rigorously definable, and the time complexity is brought much closer to the theoretical ideal, without having to hand-roll an unknown “perfect” algorithm.

I’m just guessing that something as rigorous and high-stakes as satellite collision-avoidance is going to be made less hand-wavy than, say, a picture-based chat app. I’m sure they also compared and weighed throwing in “less rigorous” variables like historical satellite-avoidance statistics.

I'm sure that somebody will eventually put a microprocessor on a kettle, one that renders said kettle useless once it breaks too. A Keurig coffee machine is essentially that sort of machine to overly complicate a simple device.

There are heuristics that can be used to optimise the search for the least expensive avoidance tactic. That cost itself might be valued in terms of camera time, fuel mass, solar panel insolation, etc. Then the orbital tracks have to be analysed for the purpose of collision prediction, and potential collisions along the intended new course. It stands to reason that there are non-NN AI tools available to help with this mammoth task.

“AI” doesn’t mean exactly “neural network” since there are other tools in the AI toolkit including:

fuzzy logic

expert systems

declarative logic (eg: Prolog)

heuristics

Markov decision process

(There are likely many more)

These tools all have immediate utility in the process of analysing orbital information about a vast number of satellites to determine likely collisions in the near to medium term future. Simple heuristics could be “don’t bother checking for collisions between satellites whose phase angle closing rates are more than two days away from zero” while fuzzy logic would help sift through the mountains of potential collisions to identify the cases where there is higher probability of a collision (fuzzy logic is an AI tool, despite being relatively straight-forward maths).

All of the maths involves uncertainty, since satellites are small, fast objects far away from the nearest detector. The applicable AI tools are those for making decisions based on vast amounts of uncertain information (or rather, data with varying error ranges).

We have fuzzy incomplete data on orbital objects. So we have to guess where they will be in the future. Mathematical models work to some degree, but you can get more accurate predictions using machine learning.

This is an almost perfect use case for ML.
Lots of out of date and changing data part of which is the hard math calculations of the expected orbits added to which are computational unknown variables like variations in atmospheric drag.

Yeah, is there an international council or group in place for this sort of thing? If not, I feel it’d be a more effective method of correcting possible collisions in the future, rather than each spacefaring entity attempting communications directly to each other. Though I can imagine that having a middle man could delay the communications, but that’s just personal opinion, I could be totally wrong .

There are protocols though for what ships are supposed to do when two ships come near each other and how to behave when passing. That includes emergency radio frequencies which are supposed to be monitored continuously by ships over a certain tonnage and rendering assistance in an emergency (for something like the Titanic... those "international law" rules created after the Titanic sank).

It isn't necessarily forced, but most countries have legal code to enforce their nationals and citizens to conform to those generally accepted rules and failure to follow those rules can get your shipmaster licensed revoked.

For a country like Bangladesh, they might get away with flipping the bird at water safety rules, but they aren't exactly a major country for international shipping. Surprisingly even flags of convenience like Liberia and Panama have legislation to enforce at least basic rules of behavior for ships licensed through their countries.

Yeah I don't think there is. There should be some "International Space Traffic Agency" or something that would have access to precise orbital data and would order satellite operators to make adjustments to prevent collisions. It's gonna be hard when the biggest satellite operators will be the US and China though.

Sort of true. The USAF provides information for collision avoidance as a part of its overall mission to defend American interests in space. They track space debris and object in space to distinguish benign and civilian space assets from potential military spacecraft that could be a threat to the USA, including potential ICBMs and nuclear attacks from space.

In the interests of diplomacy they provide this information to other interested countries and exchange data with those willing to cooperate. They also provide this information as a service to American citizens. As an international traffic agency, they really aren't that. The Outer Space Treaty requires publication of orbital elements for tracking purposes and identifying the responsible country for indemnification purposes (aka if the satellite actually does collide or crashes into the ground... the responsible country promises to be the insurer of last resort and will pay for all damages the spacecraft may cause). To that end, the USAF also notifies other interested parties if American national assets cause damage, like the crashing of Skylab into Australia in the 1970's.

Except in the space case, you can predict the potential collision weeks or months in advance, so there should be no need to make decisions at the last minute. Maybe not so long in this case where it's deorbiting, but there should never be time-critical changes required to avoid non-maneuvering satellites... there should always be at least a few days' warning.

Except in the space case, you can predict the potential collision weeks or months in advance

Not in all cases. Even the moon doesn't follow a perfect orbit. Satellites are constantly a bit off from the mathematically predicted orbits, and it gets worse when satellites can maneuver. If you read the tweet, the mathematical prediction of the orbits changed over just a few days, or maybe hours. Atmospheric drag can vary depending on weather, what the sun is doing, etc., earth gravity varies by location, the effects of the moon, etc.

That's true now, but in the future there's going to be a lot more satellites, so the chances for collisions and therefore the need to communicate between satellite operators is going to start increasing very fast if constellations like Starlink become common. It's going to be pretty inconvenient for every one of the operators to be in contact with everyone else, so some kind of a intermediary might be really helpful even if time is not that critical.

Not a bureaucracy, but coordinating entity. Such entity would have emergency phone numbers of people responsible on operator side, etc. So a simple technical comms failure wouldn't block action.

For example in my home country banking transfers are handled via an common non governmental organization of which most of the banks are members (only some small banks don't belong, but then they associate with bigger ones who serve external transfers for them). In effect everyone's money arrives in hours, noone is using checks because you can just send transfer and its on someone's account much faster and requires no action on their side, it cuts out multiple ways of fraud, etc. It's so much better than in the US.

What you describe IS how money is transferred between banks in the USA. That the banks decide to sometimes decide to hold onto money for a while to play with interest is a different matter. I recently did a transfer, and it took just minutes. If you have transfers that take longer, blame your bank, not the system.

No, it's not what I describe. CHIPS is for large transfers and Fedwire is complex (with complicated point to point handshake). US banks typically treat wire transfers as a premium service and charge accordingly. Moreover, setting up a transfer to some random person account is often troublesome and complicated.

What I mean is a system for sending anything down to pennies; yes if I owe my friend some pennies I'd just send them bank transfer. In the US I'd use PayPal or write them a check.

PayPal started as individual to individual transfers service for a reason. It would be mostly pointless in if small individual transfers could be sent fast and reliably between any banks.

ICANN is a bureaucracy that can take years to resolve disputes, yet if I need to talk to a legitimate webmaster about their site I can get the contact info in just a few minutes.

It's possible to facilitate rapid communication even if the managing entity is sprawling and unflexible.

A registry of satellite operators and their emergency contact tree should be relatively simple to set up. One already needs regulatory approval to launch; it is reasonable to require accurate contact info in exchange for a license to operate.

I haven't been really following how any big players are responding to Starlink, but the initial statement from ESA I saw that seemed to single out SpaceX and make it seem unusual they were having to do anything (when they do, I believe something like 28 similar maneuvers a year) and the grandstanding about how Starlink is going to make manual monitoring impossible... Just came across to me as petty sniping.

To me it almost seems like they're trying to make it seem like Starlink will be a disaster. But I'm always pessimistic.

ESA supervisor on duty:

"Look their satellite that is in the process of being decommissioned almost hit our satellite."

ESA employee:

"Sir...We didn't even try to contact them or even notify them.. so how will save our asses?"

ESA supervisor on duty:

"We will make a press release stating they refused to move it so we had to move ours instead."

Edit: yes they did try to contact SpaceX. I was purely referring to the press release they called that was, in my opinion , very premature and half assed. You don't call a press conference that could destroy a project without proper info. IF this had KILLED Starlink as a result of said press conference well....i would be very sad at society and to quote Futurama:

Personally, I’m getting tired of the people who sit around waiting for someone to defend SpaceX so that they can accuse them of being fanboys who think SpaceX can do no wrong.

And while there are certainly some here who’ve “drank the SpaceX Kool-Aide”, would it kill you and all the others who keep doing this to politely explain what they disagree with rather than attacking the other person? This constant “fanboy” bashing is ruining the atmosphere of this forum. It’s really toxic.

I feel the exact opposite way. I feel that good discussions are often hindered because critique against SpaceX is dismissed and it's all about "Old Space" just being afraid of SpaceX and companies doing hit pieces agains Musk and what not.

The original ESA tweet was a hit piece worthy of scorn. Critique justified.

SpaceX screwing up their notification chain is problematic and should not have happened. It's an especially bad look during this accelerated testing phase, particularly when the whole effort is under such scrutiny. Critique justified.

I was reserving judgement until SpX responded; now that they have it seems clear that both parties screwed up. (SpaceX originally and ESA in their hatchet attempt.) I trust that SpaceX will admit and correct their mistakes. Not sure I can hold that opinion of ESA any more.

Instead of conversation, though, an event like this seems to generate all kinds of FUD. In particular, speculation that extends a failure like this to impugn their QC processes in other parts of the company without evidence.

So we immediately take a negative spin on it and make a press release stating they refused to move it? I would have waited a little longer before I decided to try to destroy a majorly important project with partial information on hand. They CALLED a press conference before even waiting for a official response.

They could have moved their sat and WAITED but they decided to press release...with literally no info.

Do you have a link to the press release or press conference? I can't find one.

All I can find are articles from yesterday or the actual ESA tweets that made it sound like they made the decision to move on their own. or articles from today talking about basically the statement in this post mixed with the same info from yesterday.

Gonna go out on a limb here and say they didn't try harder to contact SpaceX because it just wasn't a very big deal. It apparently wasn't even worth a phone call, the operator didn't hear back from an email, hit the button, and moved on. Then someone else decided to get some publicity off it.

Is there no escalation process? Both automatically internally for SpaceX when pages go unresponded, or more manual processes (on-call phone numbers, back-up on-call, and/or executive phones/pagers). It's not unusual, holiday weekend or not, for pages or phone calls to get missed, but there needs to be processes in place to mitigate that.

I'm guessing this is a pretty new process for spacex. There probably isn't a ton of on call work so people might not be used to getting paged. It could be getting escalated but if nobody was answering it doesn't matter.

I wonder how close 1 in 10,000 or 1 in 50,000 is in terms of the actual closest distance between the 2 satellites as they pass each other? I believe for airlines for example 1,000 ft of vertical separation is required.

Probability of a collision is a factor of the uncertainty error. Basically, uncertainty error is based upon the last known ephemeris data of the satellite, or the last radar or optical observation. Satellites move so fast with so many different and not necessarily measurable forces acting on them at varying times that we don't actually know precisely where the satellite is at any given instant (to within several meters), so a satellite's position looks more like this: "Here's a bubble where it should be based on our current readings of where it was. The bubbles of the two satellites overlap, but since we don't know exactly where within those bubbles those satellites are, here is the probability of them colliding based on a million monte-carlo runs done by some extremely powerful computers taking their best guess at it."

It reminds me of similar calculations oil companies do while drilling directional wells. Basically they have a cone that starts from the surface penetration point and compare it to the cones of the other wells in the area.

What would cause a satellite orbit to change? My simplistic thinking is that you would know its position and orbital calculations and could forecast where exactly it will be for a decade or more. Like planets or the moon. What is causing them to shift orbital parameters?

First of all, atmosphereic drag. Yes, there's enough molecules up at orbital altitudes to impart drag. Even the ISS has to do a boost once or twice a year to re-raise the orbit because all those solar panels have a ton of drag.

Another is called 3rd body (or "n" body) effects. The moon and the sun get a vote on where your satellite goes because of their proximity and mass, respectively. All the other planets gently tug from a distance too and have more effect if they all "stack up" in a line relative to earth, just less so than the moon and sun because of their mass and distance.

The earth isn't perfectly round (it's "oblate"). It's sorta fat at the equator, enough so that the effect of gravity is actually stronger at the poles because as you pass closer to the poles you're technically closer to the center of Earth's gravitational well. This causes orbital precession where your inclination can subtly change over time. It can also flip your apospsis and periapsis.

The earth isn't perfectly round (it's "oblate"). It's sorta fat at the equator, enough so that the effect of gravity is actually stronger at the poles because as you pass closer to the poles you're technically closer to the center of Earth's gravitational well. This causes orbital precession where your inclination can subtly change over time. It can also flip your apospsis and periapsis.

What I find annoying is that certain items won't deorbit themselves. I'll leave something in an orbit that clearly does a hard pass through the atmosphere and won't deorbit unless you fly it. And I can't leave ion engines running on long burns to raise apoapsis while I release other satellites.

There’s another problem. The methods the space tracking community use to generate an “orbit” are messy. Optical sensors have trouble telling altitude (bright and far away vs dim and close) while radars have trouble with moving objects (in track, the left-right). Basically you need an even mix of the two to generate the best possible track. However that’s not practical. That drives positional uncertainty and increases the apparent likelihood of collision. Only additional observations will refine the orbits and change the probability of collision.

The best data you can get is the data off the satellite telling you where it is, but you only get that once a day or so if your sat is making contact with a ground station to offload data, barring a relay network.

Laser trackers can get you instantaneous orbit data, but they need to know where to aim so theyre usually bundled with optical sites. And you can't shine them at everything cause imagery satellite optics don't like getting hit with lasers.

Is it possible this will improve for Starlink satellites with intersatellite links allowing near constant position updates? Could they [conceptually] add more cameras beyond star tracking or a radar package to improved orbital data on objects near to their orbital plane?

That's a good question, and I believe with the number of sats they're throwing up there it would help prevent navigational position errors immensely if they did, not to mention take a lot of the load off ground based satellite sensors from having to populate the space object catalogues via radar and optical tracking.

Sorta, except the uncertainty error isn't egregiously large unless you haven't had an observation (either optical or radar) taken recently or haven't gotten the location ephemeris off the sat in a couple days. Most orbital data is good for useable accurate predictions within 72 hours; anything past 72 hours is not very useful because the uncertainties get too large to make actionable maneuvering decisions with.

Yes, especially because there isn't one single global clearing-house for space traffic control, and there's more satellites than ground station antennas capable of remaining in 24/7 contact with every sat at all times, and because there's a lot of junk and defunct stuff that needs tracking.

However, the USAF is "World Policeing" that problemset. They make all their observations open-source for everyone to see because it's in everyone's best interests to be able to know where everything is to the highest level of accuracy currently possible. (Of course they hide their spy satellite data, so if you want that go look at Russia or China's counterpart websites for those)

I don't think so and this is part of the global problem. Moreover, there is no independant database of TLEs, everybody is using an US Army service which can be shut in minutes for national security (or any new idea of the president of united states) or can be filtered out from their ennemy of the day (and some US military payloads are not registred).

The article's title was changed to "SpaceX Declined To Move A Starlink Satellite At Risk Of Collision With A European Satellite" (originally it was SpaceX Refused To...), but this is still incorrect. When SpaceX declined to move the Starlink satellite, there is very low risk of collision, low enough that a move is not necessary, which ESA also agreed. Yet the title makes it looks like SpaceX is putting ESA satellite at risk by declining to move.

"The European Space Agency (ESA) says one of its satellites was forced to avoid a satellite from SpaceX’s Starlink constellation, raising concerns about the impact of Starlink on low Earth orbit operations, after SpaceX declined to move their satellite out of the way."

Again, the article and its ESA source didn't mention that when SpaceX declined to move their satellite, the collision risk is low enough that there is no need to move. In addition, ESA themselves agreed there is no need to move.

"According to Holger Krag, head of the Space Debris Office at ESA, the risk of collision between the two satellites was 1 in 1,000 – ten times higher than the threshold that requires a collision avoidance maneuver. However, despite Aeolus occupying this region of space nine months before Starlink 44, SpaceX declined to move their satellite after the two were alerted to the impact risk by the U.S. military, who monitor space traffic."

What ESA didn't mention is that the risk didn't start with 1 in 1,000, it started much lower and only increased to dangerous level after their email exchange with SpaceX during which both SpaceX and ESA agreed no move is needed.

"“Based on this we informed SpaceX, who replied and said that they do not plan to take action,” says Krag, who said SpaceX informed them via email"

This is technically true, but it didn't mention at that time ESA agreed the risk is low enough that no action is necessary.

"As to why SpaceX refused to move their satellite, that is not entirely clear (the company did not immediately respond to a request for comment)."

It is clear now, because at that time the risk of collision is very low so no movement is needed.

I feel like the mess that this has turned into is almost entirely O'Callaghan's doing. The unsourced quotes on twitter, this piece of... "media"... Essentially everything... I posted something over in lounge where Krag praises SpaceX's response to this situation. I don't know if he has an agenda or if he is just in it for the clicks, but AFAIK there was ZERO animosity in this situation before he (Jonny) showed up and people started quoting his twitter posts and that article.

How would you react if you ask someone "hey uh maybe you should move your shit I'm worried we might crash", they answer "nah should be ok" and you say "well ok".

Then, you get new info. You say "dude I really think you need to move it looks really dangerous" and there is straight up no reply. I'd just feel I'm getting ghosted (which companies do all the time to avoid commiting to anything which might make them liable).

Besides, I'd argue SpaceX has a responsibility to not cause more space debris, especially considering how many satellites they plan to send up. "sorry bro my email totally broke" (or whatever they claim was the reason) is certainly not an adequate way to handle space debris.

It was not their responsibility to move out of the way (which ESA said as well). But SpaceX demonstrated either an inability or a lack of desire to actively mitigate space debris considering they did nothing when the new data was available which I think is what everyone needs to be concerned about.

How would you react if you ask someone "hey uh maybe you should move your shit I'm worried we might crash", they answer "nah should be ok" and you say "well ok".

Except this is NOT what happened, ESA did NOT ask SpaceX to move Starlink 44, this is a critical piece of information the author of the Forbes article refuseddeclined to include in his article, instead he only mentioned it on twitter

So with this fact the exchange would be more like this:

ESA: "hey uh looks like there is potential for a crash"

SpaceX: "nah should be ok"

ESA: "ok"

Later

ESA: "it's getting really dangerous, here's our plan to move away"

SpaceX: ....

ESA: "ok, we're executing our plan to move away"

SpaceX: ....

Besides, I'd argue SpaceX has a responsibility to not cause more space debris, especially considering how many satellites they plan to send up. "sorry bro my email totally broke" (or whatever they claim was the reason) is certainly not an adequate way to handle space debris.

It's a honest mistake, everybody makes mistakes, including ESA. Galileo just had a total breakdown lasting for days a month ago, the difference is nobody wrote sensational articles about it.

Yes everyone makes mistakes, but a mistake in space when it comes to space debris can mean no more easy satellites for anyone. I think mistakes are not acceptable per se. Everyone has a responsibility to try I'd argue. If you try your best and it fails then well that sucks but at least you did your best.

When you just don't answer emails and show no desire to do the right thing, that's another thing entirely.

An important piece of information is also:

“Based on this we informed SpaceX, who replied and said that they do not plan to take action,” says Krag, who said SpaceX informed them via email – the first contact that had been made with SpaceX, despite repeated attempts by Krag and his team to get in touch since Starlink launched.

It s not just this case of refusing to reply to an email (or again, the inability to if what SpaceX says is true). Apparently they have already refused to engage in discussions regarding space debris mitigation.

Yes everyone makes mistakes, but a mistake in space when it comes to space debris can mean no more easy satellites for anyone.

No, the consequence wouldn't be that bad because Starlink is in a very low orbit where debris would decay quickly, this is why they chose this orbit in the first place.

I think mistakes are not acceptable per se.

They have to be acceptable, "failure is not an option" is how we end up billion dollar satellites from NASA.

Everyone has a responsibility to try I'd argue. If you try your best and it fails then well that sucks but at least you did your best.

SpaceX is trying their best, and they're being responsible by starting the constellation at a very low orbit.

When you just don't answer emails and show no desire to do the right thing, that's another thing entirely.

SpaceX already said this is not intentional, and ESA's new statement says SpaceX has been in contact, so I'm not sure why this is still an issue.

It s not just this case of refusing to reply to an email (or again, the inability to if what SpaceX says is true). Apparently they have already refused to engage in discussions regarding space debris mitigation.

I'm pretty sure this part of the article is wrong, no other article mentioned this part, and ESA's statement didn't mention it either. The author probably just mixed this up with SpaceX not answering email after the initial contact, there's no reason for ESA to contact SpaceX before when there's no danger of collision.

Though not a justification I think a number of people are missing that in the US this was a holiday weekend. While larger operations probably have people staffed and onsite through the holidays with SpaceX not yet providing services from their sats they don't really have a need- other than this. Having people just on call is not enough for someone operating working sats but when they are not yet operational it is not surprising and is entirely reasonable. I doubt they expected any activity over weekends and holidays for a while.

I imagine that in the future, especially once service is being provided, they will maintain a fully staffed 24/7/365 facility with at least one person "in office" or "on console" during all times. At least until an AI system is proven able to take up the task well.

As the ESA points out however, and the news keeps ignoring, the lack of "rules of the road" or even "contact them here" info means this is not an easy task. This is something the UN and/or a treaty needs to take up. Some DB of whom to contact and some basic rules of the road as far as right of way. This was as much an issue due to the lack of standards/ rules as it was a failure in communication.

I also think it's good that ESA made the issue mainstream. It's quite hard optimization problem and I find it interesting what kind of rules could everyone agree on. If any.

Every movement eats into lifetime of the satellite. So it would be fair if everybody moved their satellites equally, on average. But 2 cooperating sats in orbit feels more valuable than 1 of 2000. From that point of view it would be fair if Starlink would move their sats more often than others. And then there are sats on decaying orbit, how to fairly count avoiding these? If it would be my turn to move the sat, how much would the other party charge me to move theirs instead?

I am not sure the ESA really meant to make it mainstream. I think they wanted to raise the issue within the community and to start the discussion/ progress the discussion on working out a resolution before 25k new sats are launched in the next 10 years.

I think the press took it up because:

Elon Musk = clicks

SpaceX = views

Elon/SpaceX/Tesla hate= money

It was an interesting story on a boring weekend

It was news for a few in the industry and for fans/ watchers

All of the above

Elon's disdain for marketing, PR, and comms people means that SpaceX/Starlink/Tesla will for the foreseeable future be easy targets for bad/lazy/uninformed reporting. Until the cost of not having good PR/marking equals or exceeds the cost of marketing/PR I would not expect him to do anything about it though.

Elon does not disdain marketing. What he disdains is the form of marketing that is advertising. I think his disdain/contempt for it is an ethical position and also one that he thinks is in the best long term interest of the companies he runs.

(I'm alert to this distinction because I also hate advertising and block as much of it from my life as possible. Advertising is toxic to society and to the individual. It is mind pollution.)

Fair enough, though I think he also dislikes PR companies and other people speaking for the company. I was using marketing is the broad & classical sense. He obviously likes social media but I don't think he see's that as marketing as much as interacting with customers & potential customers.

Tesla's website is marketing. It presents information about their products & services to already interested possible purchasers. (Same with the SpaceX website). But you need to actively go there to get their marketing spiel, as opposed to having it pushed on you whether you're interested or not (as with advertising).

And the Tesla twitter account is quite clearly marketing (the SpaceX one not so much, although you could perceive it as marketing to potential employees). Elon often retweets Tesla marketing tweets while also engaging in customer interactions (public relations). But again, you only see this stuff if you subscribe to those accounts.

I think you have gone way beyond with those points. A website, social media, and the like is base. I would not call it marketing and most companies that have just that do not have a marketing dept- which is what the whole conversation was discussing. To have a website, twitter & IG you don't need a marketing department so I don't see how it changes what I was pointing out. I feel like you are getting deep into semantics without adding anything to the discussion.

Yea, as far as I can tell here O'Callaghan made a mess of this on Twitter and Forbes for the clicks / publicity. I don't think that ESA is especially above throwing a little shade from time to time but this wasn't really even about that to begin with. It was just of an example of a space FAA probably being a good thing and that to deal with the LEO comms explosion it's going to need formal technical solutions.

It could be even more complicated than that. Sure, it sounds fair that both satellites share the required dV costs of moving. But if one satellite moves, then has to move again in the future because of the first move, would that count for more than a one off move? If one satellite needed to boost anyway because it was being perturbed out of its proper orbit, should that really count towards its share of avoidance? I foresee many meetings arguing this stuff out.

Here in the Netherlands we have a saying: pas als het kind verdronken is, dempt men de put (English: only when the child has drowned will people close the well) meaning people will only take action when a big accident happenes because of it. seems like a typical case of that.

While not unexpected, it being a long weekend and them not having proper monitoring or solid on-call processes [with escalation in place] is not "reasonable". Just because their satellites are prototypes and they don't have any customers doesn't mean they aren't accountable to ensure their satellites don't pose a risk to other objects in orbit.

That said, it's really hard to know exactly how things broke down when there's a lot of self-serving drama, especially from the media who has turned this into a bigger mess than it likely was. SpaceX did say that part of the launching the prototypes was to figure out how to manage their constellation, and well this was just another one of those lessons.

Where in any of the information that has been shared publically do you see that they "did not have proper monitoring or solid on-call process"? Also, are you sure that EAS contacted them in the best way? They said they used email. That could have broken down on either end as it is not a very reliable process. You are putting a lot of assumptions on them from what I can see.

The reasonable part is that when the weekend broke the odds were so high that both SpaceX/Starlink & the ESA agreed that no moves were required so having somene on call and not on console is "reasonable". The situation changed over the weekend and due to a failure of their systems the on call person did not get notified. They did not provide more information then that. Had the ESA had very high concerns before the weekend broke they could have exchanged more direct and specific information with the relevant parties but we do not see where that happened. I never resolved them of their responsibility I simply pointed out that the process and people they had setup was reasonable for a company not currently servicing clients and that prior to the weekend/ holiday had no satelites in a collision orbit as agreed by both ESA and SpaceX/Startlink.

"a bug in our on-call paging system prevented the Starlink operator from seeing the follow on correspondence"

Right there in the quote ... the system broke, for whatever reason. The fact that they acknowledge their was follow correspondence showed the failure in the system was on their side. If email isn't a reliable enough process, then at the very least SpaceX/Starlink website and email footers should have an number to contact for escalation. If the page went out and it wasn't responded to, the system should automatically escalate to backup pagers.

All of this occured before the weekend, so you are not even using the existing information to build your narrative. I'm not saying SpaceX failed miserably, I just expect they are immature systems and processes. You making excuses for them "because long weekend" isn't productive

Things break, that does not mean you don't have a process that is solid. The ESA's email server could have gone down and then what? The failure of a part is not indicative of a failure to have a robust or reasonable process in place. Some things require Six Sigma, not everything does.

End of day this is a problem of a lack of formalized international methods. We need standards like the ITU and ICAO to come up with acceptable processes and contact information and methods. Until something like this exist I doubt there will be good Six Sigma like systems in place unless they are providing necessary services that require that kind of process uptime.

The whole point of on-call is to provide timely response to urgent and emergency situations, so it should be tolerant to "things breaking". Have you worked in a support environment before?

[And I'm not sure what your point is about the email server, they would have had previous correspondence with escalation information on it, if that was your point. I'm not saying this is an idea solution, but there are multiple ways to mitigate communication failure]

I am currently a Director of IT and have been such at large and small firms.

Not every situation and company requires five 9's of access and availability. If the SLA is such that one missed escalation is too many that that is not something that should be on an on-call but should be staffed full time. That said, I don't think that SpaceX needs that yet or that this situation called for it. If it was the ESA would have talked about making a big racket. They would have tweeted @ Elon and or other SpaceX resources, they would have talked about calling and getting no answer. Instead they opted to resolve it on their own.

As I said before, reading what the ESA has said minus the click-bait and over-hype from the media their bigger point was the lack of a formalized process internationally was a bigger issue than them moving the sat. They want to have an international process, information share, and standardized procedures. Two pilots can fail to make contact with eachother due to radio failure and they still know who goes up and who goes down to avoid a collision becuase there are accepted and standardized reponses. That does not exist for space at this time and until it does you will have a broken process no matter what you do internally.

My point about the email server was that if the ESA thought it was a five 9 service they would not have communicated over such a low guarantee communication channel. They would have asked for or insisted upon a voice channel with direct access to ensure they could reach someone. They did not so it is not a five 9 requirement on either side. It could have just as easily been that the ESA's email server had an issue and they lost communication. Fragile systems on both sides so not a five 9 SLA involved so to put that expectation on one side is not reasonable or even what the ESA was talking about if you look at what they said and the issues and concerns they raised.

That said, if email has been standard practice for the industry and they've otherwise always received a timely enough response it's not unreasonable for them to have communicated with SpaceX via this channel, regardless of how reliable the tech may be. It's hardly the first time an important process didn't have sufficient processes, checks, or backups in place. And whatever worked in the past historic likely won't be sufficient in the future.

Really I think this failure in communication was a good thing, drama aside. It wasn't a major failure, and SpaceX is working on how they will manage their mega constellation, so figuring out how they communicate and interface with other companies and space agencies is important.

I don't disagree with you on any of that. My point was that SpaceX using an on-call pager system that is falliable is equivalent to the ESA relying on email that is equally as falliable. Both can fail, have issues, and are not guaranteed services. So to ding SpaceX and yet give the ESA a pass is not reasonable. Both relied on less than top level comm's methods so neither is going five 9's. All in all as said it worked out media drama aside.

I find it very strange that they chose Loren Grush of all people to release the statement. Did they send it to multiple reporters and she was the first to report, or was she the only one? The Verge wouldn't be my first choice. Loren's pretty good, but The Verge is a essentially "lifestyle" blog(in the evolving digital age).

Satellite orbits aren't ideal, they diverge from theoretical calculations with time. Earth gravity isn't a gravity of ideal sphere, atmosphere is quite non-predictable and very significant at these altitudes, there is some limit in velocity & position measuring precision etc. So you may predict satellite orbit with only that limited precision - that's why they speak about probability.

I'm not an orbital scientist or anything, but I would guess that local deformations of Earth's gravitational field as well as the residual atmosphere would slightly change the orbital parameters of satellites around the Earth, and that considering their size it would be quite difficult to precisely tell if a satellite is going to collide with another. But again, I'm just speculating.

It's quite hard to determine precisely an object's position when a tenth of a second inaccuracy means the object suddenly is a kilometer away from the predicted point. Add 2 objects to the calculation, and a bit more inaccuracy due to Earth's gravitational field not being ideal, and several other sources of inaccuracy and you got yourself a pretty hard problem to solve, especially for predictions farther in time

Can someone explain how they did not know the heading of their satellites?

It's quite likely they do know the exact location and course of the satellites, but that's not available in real-time to all the other satellite operators. Besides which, it's always possible that some junk has detached from the satellite in orbit, so it's a good idea not to pass by too close at 10km/second.

TLDR - they do not actually know to within the size of the satellite exactly where each satellite is and that implies a probability distribution rather than a boolean.

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It comes down to the both precision and accuracy of the measurements of the state of each object and the accuracy and precision of the method to project that state forward in time.

Consider the state of an object to be its location and velocity at a specific time. We know physics so we given that state we can project forward and say where the object will be at a future time. Now lets take an example where we have two object traveling perpendicular to each other in the same plane at orbital velocity but with out the complication of gravity. Orbital velocity is about 8000 meters per second, and the satellites are of order 1 meter in size, except for the solar arrays which are perhaps 5 meters in length. To know if these two objects will collide you need to know there location to much better accuracy than their size where they are, and your time accuracy has to be better than how long it takes to move 1/10 their size. So you need centimeter level location accuracy and 1/80000 second time accuracy. I assume they use GPS for location, which is only guaranteed to less than about 8 meters 95% of the time.

I don't think SpaceX is without fault [contribution would be a more productive term though]. I wouldn't be surprised if they haven't put enough work into their monitoring and oncall processes; but I don't think you can ignore the self-serving drama from ESA and especially from this reporter. This isn't the first time there's been issues that get turned into media drama for the purpose of pushing forward ESA [or ArianeSpace] agendas within their own governments.